Despite the new capabilities and applications developed for mobile telephones each year, voice calls remain one of the most important functions for users of mobile telephones. Accordingly, mobile carriers are constantly trying to improve the quality of voice calls (also referred to as “voice quality”) within their mobile networks. For example, providers of Voice Over Long Term Evolution (VoLTE”) call services, which have been adopted by many mobile carriers as their de-facto voice call solution in fourth generation mobile networks, are constantly assessing and trying to improve voice quality of telephone calls made using VoLTE.
To assess voice quality within a mobile network, conventional techniques focus on directly evaluating the audio quality of speech included in voice calls. For example, Perceptual Objective Listening Quality Assessment (“POLQA”) is a standard provided by the International Telecommunication Union Telecommunication Standardization Sector (“ITU-T”) that compares recorded audio clips taken from voice calls between mobile telephones with pre-recorded reference sentences in order to provide objective voice quality evaluation.
Unfortunately, POLQA and other techniques that directly evaluate audio features are extremely cumbersome and costly. For example, each evaluation requires professional hardware, such as high definition recorders, headphones, and playback devices, as well as significant human effort. Hence, direct evaluation of audio features is difficult to perform on a large-scale basis. Moreover, the direct evaluation of audio features does not analyze the root cause of poor voice quality, and is thus unable to provide a mobile carrier with sufficient information gain (entropy) that allows the mobile carrier to optimize one or more aspects of the mobile network in order to remedy the poor voice quality.